Assembly and Autochirogenesis of a Chiral Inorganic Polythioanion Moebius Strip via Symmetry Breaking

摘要

Using [Mo_2S_2O_2(H_2O)_6]~(2+) and squarate dianion, we synthesized the thiometalate ring compounds [(Mo_2S_2O_2)_x(OH)_y(C_4O-4)_z(Mo_2O_8)_o(H_2O)_p]~(n-), where [x,y,z,o,p,n] = [7,14,2,0,2,4] for 1, [6,8,2,2,4,8] for 2, and [4,6,1,1,0,4] for both 3a and 3b, which are chiral and nonchiral isomers, respectively. Not only do the four thiometalate clusters show decreasing symmetry at the molecular level across the series, but the incorporation of the "addendum" {Mo_2O_8}_o unit also allows the thiometalate ring to twist. The reaction initially yields the chiral molecule 3a with a twisted ring, which undergoes spontaneous resolution upon crystallization; the reaction mixture later yields the intrinsically nonchiral isomer 3b with a nontwisted ring. In addition, the compounds are able to promote the electrocatalytic evolution of hydrogen.